Bayer Aktiengesellschaft

Silke Kratschmer

Uwe Hucks

Lothar Bunzel

Rolf Wehrmann

Klaus Horn

Steffen K&uuml;hling

Annett K&ouml;nig

Wolfgang Alewelt

Michael Prein

James Mason

Dieter Wittmann

Thomas Eckel

Friedrich-Karl Bruder

Johann Rechner

Wilfried Haese

Kaspar Hallenberger

Peter Fischer

Holger Warth

Thomas Fischer

Rolf Bachmann

Michael Erkelenz

Eike Schulz Van Endert

Franz Ferdinand Rhiel

Heinrich Hähnsen

Marco Roelofs

Melanie Moethrath

Hans Deml

Manfred Schraut

Renate Wilms

Klaus Schr&ouml;der

Thomas K&ouml;nig

Hans-Peter Hoffmann

The invention relates to a continuous method for producing polycarbonates by transesterifying diaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds. The invention also relates to polycarbonates produced thereby and products produced from said polycarbonates.

Method for producing polycarbonates

A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350&#xb0; C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Process for the recycling of polycarbonates

A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Process for producing oligocarbonates

A branched melt-polymerized polycarbonate having pronounced non-Newtonian flow behavior is disclosed. The polycarbonate is suitable for preparing molding compositions and the preparation of a variety of molded articles.

Polycarbonate having pronounced shear thinning behavior

A process for the preparation of transparent copolycarbonate is disclosed. The copolycarbonate the molecular structure of which contains more than 35 mole % of units derived from dihydroxydiphenylene is prepared by the melt transesterification process wherein the final temperature of the reaction is reached in less than 40 minutes after reaching the starting temperature.

Preparation of copolycarbonates

A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of &minus;30 to 50&deg; C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.

Storage of phosphonium phenolate catalysts and their use as interesterification catalysts

The invention relates to a novel polycarbonate and its use a material in the production of molded articles and semifinished products, especially for transparent articles such as data memories or radio compact discs, slabs, cellular sheets, films, housings, panes, especially panes for motor vehicles, diffusion glasses, but also for electrical applications or the constructions of houses.

Polycarbonate and molded polycarbonate articles

Polycarbonate blends

The present invention provides a two-stage process for the production of polyester carbonates with aliphatic dicarboxylic acids, the polyester carbonates obtained thereby, a process for the production of extrudates and molded articles from the polyester carbonates, and the extrudates and molded articles obtained thereby.

Production of polyester carbonates

A process for the production of phosphonium phenolates is disclosed. The process entails reacting a phosphonium halide and phenol in an aqueous alkaline solution. The phosphonium phenolate produced is separated from the synthesis mixture by crystallization

Method for producing phosphonium phenolates

An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed. The improvement entails the following steps (i) introducing the resulting vapor stream at the mid-height of a first distillation column, and (ii) separating the vapor stream into a top product containing high purity monohydroxy aryl compound and a first bottom product, and (iii) recycling the high purity monohydroxy aryl compound of (ii) to the reaction, and (iv) introducing the first bottom product at mid-height of a second distillation column, and (v) separating said first bottom product into high boiling bottom by-product and overhead remaining constituents, and (vi) introducing the overhead remaining constituents at mid-height of a third distillation column, and (vii) separating said overhead remaining constituents into overhead low-boiling fractions and bottom or product side stream that contains diaryl carbonate product, and (viii) recycling the diaryl carbonate product directly to the transesterification reaction.

Process for producing polycarbonate

Polycarbonate having a low shear thinning behavior

A transesterification process for producing polyester is disclosed. In a first stage of the process there is heated, in an inert gas atmosphere, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate. In a second stage there is added to the oligocondensate at least one dicarboxylic acid to form a second mixture. The second mixture is heated to a temperature not higher than 290&deg; C. in the presence of a quaternary onium compound as catalyst to form polyester carbonate. Hydroxyaryl formed throughout the process is distilled-off under reduced pressure.

Production and use of polyester carbonates

The present invention provides the use of impact resistant, stress cracking resistant copolycarbonates with particularly good low temperature properties for applications in which particularly good low temperature properties are required, e.g., for automobile construction or external applications, and new copolycarbonates themselves.

Use of copolycarbonates

A process for producing polycarbonate is disclosed. The process entails obtaining an oligocarbonate produced by transesterification of diaryl carbonate with dihydroxyaryl compound in the presence of catalysts and introducing the oliogocarbonate into a reactor that enables continuous formation of free films at a rate higher than 10. The reactor including a horizontal cylinder equipped with a heating jacket, at least one vapor outlet, a feed nozzle an outlet nozzle, a rotatable cylindrical basket having a cylindrical perforated wall and annular discs positioned at intervals around the periphery of said basket and along the length thereof, and means for rotating said basket, the interior of said basket including no central shaft, the diameter of the cylindrical basket corresponding to about &frac23; of the diameter of the horizontal cylinder, and said discs being formed of perforated sheet metal.

Growing community of inventors

Krefeld, Germany

Silke Kratschmer